A single, precise edit to one rice gene can sharply cut the amount of toxic cadmium that ends up in the grain, without reducing how much rice a plant produces, according to new research from Okayama University in Japan and the Institute of Genetics and Developmental Biology at the Chinese Academy of Sciences.

The team, led by Dr. Sheng Huang and Professor Jian Feng Ma of Okayama University and Professor Jiayang Li of the Chinese Academy of Sciences, used base-editing techniques on a rice gene called OsNramp5, which encodes a transporter protein that moves minerals from root to shoot. They generated more than 1,600 genome-edited rice lines using adenine and cytosine base editors and screened them for reduced cadmium accumulation.

One point mutation stood out: swapping a single amino acid — isoleucine for threonine — at position 441 of the transporter reduced cadmium levels in the grain by 48 percent, from 0.14 to 0.07 milligrams per kilogram. Crucially, the edit left yield and essential micronutrients like iron, manganese, and zinc unchanged. The researchers believe the mutation works by shifting the transporter’s chemical preference toward zinc, which then competes with cadmium during the mineral’s journey from root to shoot. Field trials on cadmium-contaminated soil confirmed the effect held up outside the lab.

Cadmium contamination in rice-growing soil is a persistent food-safety concern in parts of Asia, and the team’s approach offers a path to safer grain that doesn’t require trading away productivity.

Journal: Proceedings of the National Academy of Sciences (PNAS), Vol. 123
Article Title: “Genome-edited rice variety with low-cadmium accumulation in the grain”
DOI: 10.1073/pnas.2610609123
Publication Date: June 18, 2026

Source: EurekAlert